In magnetic storage systems, data is read from and written onto magnetic recording media utilizing magnetic transducers commonly. Data is written on the magnetic recording media by moving a magnetic recording transducer to a position over the media where the data is to be stored. The magnetic recording transducer then generates a magnetic field, which encodes the data into the magnetic media. Data is read from the media by similarly positioning the magnetic read transducer and then sensing the magnetic field of the magnetic media. Read and write operations may be independently synchronized with the movement of the media to ensure that the data can be read from and written to the desired location on the media.
An important and continuing goal in the data storage industry is that of increasing the density of data stored on a medium. For tape storage systems, that goal has lead to increasing the track density on recording tape, and decreasing the thickness of the magnetic tape medium. However, the development of small footprint, higher performance tape drive systems has created various problems in the design of a tape head assembly for use in such systems.
In a tape drive system, magnetic tape is moved over the surface of the tape head at high speed. This movement tends to cause formation of a film of air between the head and tape. Usually the tape head is designed to minimize the spacing between the head and the tape. The spacing between the magnetic head and the magnetic tape is crucial so that the recording gaps of the transducers, which are the source of the magnetic recording flux, are close to the tape to effect efficient signal transfer, and so that the read element is close to the tape to provide effective coupling of the magnetic field from the tape to the read element.
However, this close spacing has resulted in various tribological issues becoming more pronounced, among them, tape/head stiction and running friction. Particularly, as the linear density of magnetic tape recording increases, the magnetic spacing must be reduced, requiring smoother heads and tapes. These may be associated with increased startup friction (stiction), increased running friction, and more instantaneous speed variations (ISVs). In addition, tape-head wear may limit tape lifetime, and contact-generated debris can adhere to the head, increasing the magnetic spacing.
This friction/stiction problem can be alleviated by roughening the air bearing, but such roughening may increase tape wear. Furthermore, this roughening may be filled by tape debris or worn away by the tape. Alternatively, to alleviate stiction, a mechanism may be used to lift off the tape when stopped, but the running friction and ISVs may remain. In some cases, a mechanism to reduce friction may be utilized. In this case, the reading and writing portion of the head is surrounded with a contoured surface. This approach reduces both static and running friction, but requires some assembly.
Head-media stiction has also been addressed by making the media rougher, but, as alluded to above, this may adversely affect the signal-to-noise ratio and thus detection capability and ultimately areal density. Again, as the linear density of magnetic tape recording increases, the magnetic spacing must be reduced, requiring smoother heads and tapes.